Tracker Boats 20th Anniversary Tumbler 20oz TK17A-A100. The 20 oz. Tracker Boats 40th Anniversary is anything but an ordinary tumbler. The stainless steel is built to last, resisting punctures and rust, and double-wall vacuum insulation keeps your beverage as cold or hot up to 6 hours. The snap on lid is spill resistant and has the thumb slide smoothly back and forth, and protects from splashes and spills, whether driving on bumpy back roads or hitting some waves on the water.